Multiplex signaling system



- May 15,1928. 1,669,448

5. BRAND MULTIPLEX SIGNALING SYSTEM Filed May 1. 1925 2 sneeze-sham 1L72 i v i urn- I 5? W V IN VEN TOR 7' 2 54211146 firm/ad A T] ORA E YMay 15, 1928. 1,669,448

5. BRAND MULTIPLEX SIGNALING SYSTEMi Filed May 1. 19 26 2 sheets-sum 2:l

5 R :k 859 E Ky/5% 1! 3F 5 I L Smart finmai siifa'ii'rniihiing s aeeeaaaaaw reaa ssmaoa fro anrnn oafi Taearaoaa min TELEGRAPH COMPANY, ACORPORATION on NEW Y'oRK.

MULTIPLEX SIGNALING SYSTEM.

Application filed May 1,

It is an object of my invention to proyi de a new and improved system ofmultiplex carrier current signaling. Another oloject of my invention isto provide insuch asysteinfor operating a special station on only oneora limited number otthe carrier fi e;

quencie s. A i'urther object is to provide alocal source in connectionwith such a; tatiq i o n at n a .Pui' 1mm,. in. proper synchronisrn andphase relation with ei ele Car fillers 2, s mpone t j system. These,o'bjects and other objects of my invention, will become apparent on adiagram of a sending station, for multi-.

plexs gnahng. Fig. 21s a dlagramgo't a corresponding reoeivingstation,and Fig. 3

is .a-i iee m sh in s at- 9 aden t d nd QPT YQ on a si e, ewir requencyi in connection with a system such as disclosed in Figs. 1 and 2.

he ni'otor M in 1 drives the various n r or G12aG2ill lWG3 1 9 iz qe e 11, rents of difierent frequencies wh ch are preferably harmonics oi" afundamental he 1 13 2 5?: T mir fi r m ie 'es ii 'e mt such" as G goesto phase splitter from which two components of the same frequency 9Oapart in phase g0 tovth e respective transformers whose primary windings are 37 and S. Current of one phase transmitted through the winding37v is'coin trolled b the keys K and K The key K reverses the phaseoi'this component of,

e i n 'c o t r W t its Amen ties as the lre'y K changes the magnitudewithout affecting the phase. V p Thetwo components of current 90 apart"in phase and each affectediby phase reversals and magnitude changes asdeten mined bythe operation of the tour keys "K K K; and K aresuperposed in the input to the filter F from which they pass to thelineZ I c 1 l At the receiving end, these currents pass through theadjustable artificial line N's and the amplifier A and are separatedthrough 1926, Serial No. 106,098.

respective band filters such passes only the current of thesame fre qe'n'cy a P e by efilte F3 at the sending end. Accordingly, the outputfro in fi er c mp s .two mpons i 9 f on par i p' sei a h re rsed in phae-iron me t m -e a rv riei l in mag i de; m im i .t i.a deter ne by' h pQ o e-t ssndi'ns eyslin Ki,

sI- Ki- Th se'. ec i d, c r ntee maoa modifications, in the I receivedcurrent, so

that the output from the network: SQ Pur u m dified r -Q1 1 oi the anmia a r qu n y to which h iba d lte il l is approp e T is utpntnur eat mi n rk r itesft esy s mmaus.v

mo or S ni yns wn' m ith. t eim e zi M iii e ndi gend', it m qrfiM. iv sl the ge to s rl, i-i at eason, oies corresponding/to those of thegenera;

e 1, e ma lt e ng e qAQ Ql'dff lyr h gen ra or T3 del st lurrent heseeque yies pa s d. by; eiband, filter. flTh sicurr nt cfr m the sea ater;T3 goe hroug e ph s s i t endnh se;

pli wn and .p qd ce twqlj le t s s Ineitive f apar in Pha 91i which isapplied in the grid circuits of th e e e rs. 1 a d Dina-I i the ot r nagrid circuits of the detectors D and D e. detesto jDl h pola iz d rlay, 1. .31, 0

in i s plate rc hose armature. st nds one way when the receivedelectromotive force a d e ocally; g ne ated e ebtrema-g re f c i p a e ge t, d stand the Opp e-W y w e they ii ii phaseenr;

p si o .Hfi e th re ay lBi, ism ee'ml si slve to reversals of phase onone component of received current.

The relayNR is a neutral es egs in magni u e, d? the for t responds onlyto magn tude changes on one of the two componentsot rece ved currentThus it Will-be seen-that each otthe four relays PR NR 1 1R and NR;answers only no fiuence d by phase reversals, but. responsive 10.3

to the operation of a corresponding key at i the sending stat-ion.

r The attenuation on the line may vary somewhat. from time to time, andto compensate for this a voltmeter relay V is bridged across theoutputifrom the network SC and operates automaticallyto adjust theartificial line N. so as to maintain the voltage on the said voltmeterrelay V substantially constant. Since the artificial line N is in thepath of allthe received current components, they willall be held atsubstantially a constant level as they come into the various receivingnetworks.

Fig. 3 shows two sending stations SS, and

SS like that shown iniFig. 1, and two re ceiving stations RS, and RSlike that shown in Fig. 2, and Fig. also shows a way station adapted forsending and recelvlng on one only of the multiple frequencies employedin the system of the foregoing mentioned four stations. i

By means of the branch conductors115, signal modified currents from thesending station SS of one particular frequency are taken off and passedthrough the band filter 116 and the adjustable artificial line N". Thesesignal modified currents go to a re- V ceiving network like that shownin Fig. 2

where they are indicated respectively in the receiving relays PR N R PRand NR The received currents through the band filter 116andtheartificial line i also go over a multiple branch circuit to the delaynetwork D andthence to the signal compensator SC shown at the bottom-ofFig. 3. This network SC consists of resistances and reactance elementsprovided with switches I controlled by the relays 94, 95, 96 and 97.

These relays in turn are controlled by armature contacts associatedrespectively with the receiving relays PR PR NR, and The arrangementissuch that as the signaling changes in the received current operatetherespective relays of the receiving network they cause OlFClllllchanges in the network SC toc'ompensate, so that the output current fromthe network SCfover the conductors 86 is a purecurrent of the carrierfrequency unmodified by the signal changes. Thiscurrent goes through theamplifier 87 to the input for the receiving network across the points'51 and 52, the same as in Fig. 2.

Current of the same frequency goes through the'phase shifterPSh over theconductors 118 through the phasesplitter PS7) for varying attenuationbythe adjustable artificial line N, the same as in Fig. 2.

It will be seenthat the system of Fig. 3 is designed for co-operation inamultiplex signaling system at only one of'itsinany he quencies. At thestation shown in this figure, there is no requirement for generating thefundamental frequency of the multiplex f system, nor anyother harmonicthan the harmonic current of the single frequency statio I'claimr i HI 1. In a multiplex carrier current signaling system, the method ofoperating at a station at one ofthe various carrier current mployed forreceiving and sending at this i frequencies independentlyof the othersuch" frequencies, which consists in filtering the current of thatfrequency to .a "receiving network, compensating the signalmodifierstions in such current and applying it. to cooperate with thereceivedcurrent in the re- I ceiving network. I

2. In a multiplex carrier current 'signaling system, the method ofoperating a station at one of the variouscarrier current frequencies,which consists in filteringthe current of that frequency to a receivingnetwork, compensating the signal modifications in such current andapplying it to coop erate with the received current in the receivingnetwork, and also applying it for 'send ing on that same frequency.

In a multiplex carrier current signal-' ing system, the method ofoperating a station at one ofthe various 0&11161 current frequencies,which consistsin filtering-the said cur- 1 rent of that frequency withits signal modifications to the said station, determining thereby alocal current of the same frequency freed from signal modificationsand-:comblnlng thereceive'd signal modlfied current with the said localcurrent freed from sig nal modifications to operate detectors to dis-.criminate a plurality cally of a current of the same frequency butunaffected by signal modifications and combining this current with thereceived current,,to detect the signals conveyed by the first namedcurrent of firstwmentioned fre g quency.

of message channels -in the said received current. p I

4. T he method of receiving on acurrent of a single frequency, whichconsists in determining by said current the generation 10 5. The methodof receivingon a current of a single frequency, which consists in determining by said current the generation locally of a current of thesamefrequency, but unaffected by signalmodifications and combining thiscurrent with the received current .to discriminate among a plurality ofmessage channels on said current and detectthe signal 1nd1cat1ons n the;respectlve channels. 6. In a multiplex carrier current slgnal' ingsystem, a station adapted to operate on a a single carrier frequencycomprising a retion at one of these carrier current frequencies withoutthe need for developing the fundamental for such operation whichconsists in filtering the'current of that frequency to a receivingnetwork, compensating the signal modifications in such current andapplying it to co-operate with the received current 1n the receivingnetwork.

In testimony whereof, I have signed my name to this specification this29th day of April, 1926.

' SMART BRAND.

